The World Health Organization (WHO) estimates that globally there are approximately 50 million people with multi-drug resistant tuberculosis (MDR-TB). Recognizing this threat, public health agencies throughout the world have emphasized the importance of expeditious detection of drug resistance and the implementation of appropriate therapy. Conventional laboratory methods used to confirm the diagnosis of TB by isolating M. tuberculosis and performing antibiotic susceptibility testing (AST) can take weeks due to the growth rate of mycobacteria. Using the latest detection methods, which are routinely available in developed countries, can provide culture results in as few as 4-7 days with subsequent antibiotic susceptibility profiles in another 4-5 days in some cases. These sophisticated tests are very expensive and must be performed by trained technologists; this makes them technically and financially infeasible for use in developing countries where MDR-TB is the greatest threat. Dr. Bill Jacobs addressed the need for a new diagnostic by modifying a mycobacteriophage (a virus that infects mycobacteria) to incorporate the firefly luciferase gene (FFlux); mycobacteria infected with phage produce light upon addition of the substrate luciferin. The light can be detected and quantitated by using a device called the Bronx Box; a camera connected to a computer. The test is performed in less than forty hours in a six-welled chamber/manifold which contains antibiotics. The Bronx Box device and accompanying test manifold will provide an easy-to-use, inexpensive, clinical diagnostic test with a faster turnaround time than current methods. The long-term goal of this proposal is to continue the commercial development of the Bronx Box and make this test available in clinics throughout the world.